Understanding Vitamin D Deficiency

Vitamin D deficiency has been linked to depression, cancer, and even heart attacks.  But are these claims true? Should you get your Vitamin D levels checked? The House Call Doctor separates Vitamin D facts from fiction.

Sanaz Majd, MD
4-minute read
Episode #150

What Are Normal Vitamin D Levels?

When measuring Vitamin D levels, doctors order a metabolite of Vitamin D referred to as 25-hydroxyvitamin D.  The lower limit of normal is somewhat controversial, but most experts agree that it should be somewhere between 20 to 30 ng/mL. 

Who Should Be Tested?

Not everyone needs their vitamin D level checked, despite all of the media hype.  Medical guideline recommendations are to test those who are at risk for low levels, such as·

  • Elderly patients who are in nursing homes or are home bound

  • Elderly patients who have had falls

  • Patients with intestinal disease such as Crohn's and Celiac

  • Patients who have had surgery that removed any part of the intestines, such as in gastric bypass operations

  • Patients with kidney or liver disease (these organs help metabolize Vitamin D)

  • Patients with osteoporosis or Osteopenia diagnosed on a bone density test

How Much Vitamin D Do We Need?

The typical adult needs about 800 IU’s of Vitamin D daily (elderly home-bound patients may need more).  Therefore, if you don’t have a risk factor for deficiency, the recommendation is to make sure to maintain this daily intake – whether it’s through the diet or a supplement (or both), rather than measuring blood levels. 

Supplements are sold in two various forms – as cholecalciferol (Vitamin D3) or ergocalciferol (Vitamin D2).  D3 is preferred over D2 because it’s the more naturally-occurring form of the vitamin with likely improved absorption rates.

In addition to Vitamin D, calcium is a key nutrient for bone health.  For premenopausal women, 1000mg of daily calcium is also recommended; the recommendation is slightly higher, 1200mg, for postmenopausal women.  It’s always best to obtain your vitamins through the diet, but if you are lactose intolerant or just simply have low dairy intake, then supplementation is key.

If you have a risk factor for Vitamin D deficiency, make sure to bring it up to your doctor.  Otherwise, make sure to get the appropriate amount of this nutrient every day to prevent problems later on down the road.

As for Vitamin D preventing heart attacks, strokes, cancer, and depression?  There is no good evidence that these claims are true in the least bit.

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Medical Disclaimer
Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.

About the Author

Sanaz Majd, MD

Dr. Sanaz Majd is a board-certified Family Medicine physician who graduated from Drexel University College of Medicine in Philadelphia. Her special interests are women's health and patient education. 

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